Alastair Cook finds his old self at New Road as Essex take a grip

For a bowling attack which had just spent an entire day in the field without taking a wicket, the sight of Alastair Cook walking out to bat must have been dispiriting.

Sure, Cook hasn't been in the runs this season. His six previous innings had realised only one score above 15 and none of 50. But he was always going to come good. Even before this match, he averaged 111.25 in first-class games against Worcestershire on this ground. Putting him up against this team at present is like presenting an arachnophobic with a tarantula sandwich.

So it was that, served a slow track offering bowlers little but toil and heartbreak, Cook gorged. He is, perhaps, just a little more expansive than when he last played for England - just a bit more willing to have a dart outside off stump - but the basics of his game have not changed for many years. Block, leave and if the bowlers stray, especially on to his legs, put them away. If you've seen him bat before, you can imagine this innings. This was the 68th first-class century of his career and his 25th for Essex. For much of the day you wondered who would go first: Cook or the cathedral.

Spare a thought for those Worcestershire's bowlers. They came into this game having not taken a wicket in the Nottinghamshire second innings last week - Haseeb Hameed and Ben Slater batted for four sessions to secure a draw - and then went through the first session of this match with the same result.

They did not, by any means, bowl poorly. But not only is this surface offering them little, their fielders offer them even less. Four chances went down - none of them easy, to be fair - with Nick Browne put down by Daryl Mitchell in the slips on 8 and 13, off Dillon Pennington and Charlie Morris respectively, before Ben Cox dropped Tom Westley, on 45, off the admirable Ed Barnard. Then, from the final ball of the day, Dan Lawrence, on 29, was missed by Cox off Pennington. To make matters worse for the bowler - who cried out in anguish - the ball flew away for four. It was telling that, when a wicket did fall, it did not involve a fielder.

By then, Worcestershire had been in the field for nine-and-a-half hours (or five sessions and 25-minutes, if you prefer) without success. They were also without their captain, Joe Leach, who was rested as part of the club's rotation policy. Jake Libby therefore became Worcestershire's latest captain, which gave a new opportunity for young pace bowler Pennington.

But pace is a dubious asset on this surface. Particularly against a man as adept against it as Cook. And hard though Worcestershire's bowlers tried, they just couldn't coax enough out of this surface to beat one of the broadest bats in the business.

"On wickets like this, you really hope those chances stick," Worcestershire's bowling coach, Alan Richardson, said afterwards. "I thought the boys stuck at it really well. It was slow again so you had to be really disciplined with bat and ball."

In truth, this wasn't the most riveting day's cricket. With Worcestershire making Essex work for the runs and Essex refusing to take chances, it was a day of steady accumulation. A pitch as slow as this simply doesn't allow for much else.

That is an observation not a criticism. The square here was under water only a few weeks ago (this ground floods regularly during the winter) and, since then, we've had a bitterly cold April which will have done nothing to promote grass growth. It's all very well the England management calling for "better" pitches; we have to be reasonable with our expectations. It's almost a miracle they are playing here at all.

Cook's innings was chanceless. Once, on 29, he scuffed the ball just short of mid-on off Barnard. And once he was fortunate to see the ball scurry to the third man boundary off the face of his bat as he attempted to leave one. But generally, there was a sense of inevitably about his century long before it was achieved.

Still, it was revealing that, after all his success, Cook admitted to some feelings of insecurity after his modest start to the season.

"I've been struggling for rhythm this year," he said. "It's a horrible feeling when you go home knowing you haven't delivered. I can't remember the last time I batted so long. You almost forget you can do it. You have to trust yourself and know that you can score runs and you will score runs.

"It was a grind today. But it was a nice wicket to bat on. It's very flat. So it was about getting in and making it count. I wanted to go big."

It probably tells you everything you need to know about Cook's hunger for runs that, after his dismissal, playing on as he attempted to cut, he looked utterly aghast. All those runs, all those centuries, yet still he's hungry. This was his third first-class century against Worcestershire at New Road in a run that dates back to 2005. He now averages 112 here for Essex.

With Tom Westley he put on 139 in 48 overs. While Westley, too, had to earn his runs - his half-century took 144-balls - he did play some impossibly elegant shots. In particular, there were successive on-drives for four - one off the front foot, the other the back - which were things of real beauty. Not for the first time, the thought occurred that while you might want Cook for his reliability, it is Westley's batting with which you could fall in love.

Whether this pitch will remain flat for the rest of the match remains to be seen. That last delivery of the day seemed to have more life than anything that went before. It may well be that Essex are well on the way to establishing a match-defining position.